During the last week Chandra completed the observing schedule as
planned.

A flight software patch was uplinked on on Dec 23 which updates the
safing action SCS-78 to include commands to power-on side-A of the
valve-drive electronics after it has been powered-off. This patch
ensures that Chandra will have the capability for unloading angular
momentum follwing a safe-mode transition in which the redundant
on-board computer fails to start-up nominally. Real-time procedures
were executed on Dec 24 to dump OBC-A memory as a follow-up to the
patch. The dump will be used to update the baseline memory image
maintained on the ground

An aspect camera dark current calibration was performed from the
on-board loads on Dec 21. An assessment of the data indicates
nominal aspect camera performance and that the number of CCD warm
pixels is increasing at the expected rate.

A Chandra press release was issued on Dec 21 describing observations
of a gigantic tail of X-ray emission that has been found behind a
galaxy plowing through the galaxy cluster Zwicky 8338. With a length
of at least 250,000 light years, this is likely the largest such tail
ever detected. Scientists used Chandra to discover the tail, study its
properties and learn how this X-ray tail affects its cluster
environment. For details see:
http://chandra.si.edu/press/15_releases/press_122115.html

The schedule of targets for the next two weeks is shown below and
includes an observation of Cyg X-1, which was accepted as a Target of
Opportunity on Dec 9 and is coordinated with NuSTAR, an observation of
PSN J10520833+3256394, which was accepted as a Target of Opportunity
on Dec 22, observations of SDSS J0859+0426, 2MASS J08055713+0417035,
SDSS J1509+0304, SDSS J1019+2119, and SDSS J1104+4345 coordinated with
ground-based observatories, and an observation of 2MASX J04595677+3502536
coordinated with NuSTAR.